The present invention relates to a lithographic film material for making a lithographic negative film in the form of an optical stencil by the use of a thermal ink-transfer printer.
Mask plates, on which transparent words and/or illustrations are optically formed in stencil-like fashion (hereinafter referred to as optical stencils), are used to print words and/or illustrations on photographic prints. Such an optical stencil generally is made so that words are printed on photographic paper as a primary original with a photographic printer. The primary original then is copied or printed on a negative film material such as a lithographic film (hereinafter referred to simply as a lith film) to make a secondary original as an optical stencil. This procedure, which includes correcting and developing the primary and secondary originals, consumes time and takes much trouble, and further, requires special techniques.
In recent years, it has become popular to make an optical stencil by forming transparent words and/or illustrations on a lith film by a thermal ink-transfer printer. However, light-opaque layers of the conventional lith films are difficult to peel or remove when the transparent words and/or illustrations are printed with thermal ink-transfer printers now commercially available. Because the use of lith films requires a special peeling system for peeling off the light-opaque layer of the lith film printed by such a thermal ink-transfer printer, the optical stencil is neither economical nor technically advantageous.
Therefore, it is an object of the present invention to provide a novel lithographic film material from which a negative lithographic film can be made as an optical stencil with conventional thermal ink-transfer printers.